Answer:
The correct answer is C
Explanation:
In asexual reproduction method, the offspring generated is identical genetically to the parents. But this is not the case in sexual reproduction. The reason being that the gametes or sex cells produced has only one set of chromosomes and are therefore haploid after the process of meiosis. Meiosis is the process when the offspring formed has chromosomes from two parents and is not identical to the parent. Only certain characteristics are inherited by the offspring from both the parents and offspring has different set of characteristics.
There is a process of assortment taking place inside the cell when the double set of chromosomes becomes one set in a gamete. Out of the pair of chromosomes, there is a random selection. Due to this random assortment, there is a genetic variation between the gametes as the gene alleles on the chromosome are not the same. This principle is said to be the Mendel’s first law of segregation.
Another process of combining chromosomes is the crossing over during the meiosis stage which results in variety of chromosomes. We can say that recombination is possible.
Hence, we can note that during assortment and crossing over, there is no chance for two offspring to be identical to the same mother or father with the exception of identical twins. In the case of identical twins, the genetically identical characteristics develops from same fertilized egg.
From the above process, the structure of gene gets changed creating a variant that can get transmitted to next generation. The change is caused by altering the single base units of DNA or rearranging larger section of genes.
